Stabilized hydrocarbon compositions and antioxidant therefor



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2,843,468 i P Patented July 15, 1958 STABILIZED HYDROCARBON COMPOSITIONS 5 AND ANTIOXIDANT THEREFOR W. Thompson and Wayne V, McConnell, Kingsport,

' I Tenn., assignors to Eastman Kodak Company, Roches- 1 ,ter, N. Y., a corporation of New Jersey NoDrawing. Application July 22, 1954 H 1 Serial No; 445,157 1 v 11 Claims, c Jmmj p This invention relates to the'stabilization against oxidation of hydrocarbon compositions normallyfsubject to oxidation and to new and improved antioxidants. 1 "'Many" organic compositions, and particularly hydrocarbon compositions, are subject to deleterious oxidation i during storage oruse. Thus, for example, the petroleum derivatives such as gasolines,'oils, and the likefaswell as such materials as both natural and syntheticrubber,

generally have to be stabilized against oxidation for satisfactory results. In the case of the petroleum products,

and particularly the gasolines such as straight-run gasolineg thermal or catalytically cracked gasolines', leaded gasolines such as aviation fuel, jet fuels, and the' like, undesirable soluble and insoluble gums form due to oxidation, A t

accordingly an object of this invention to provide and useful antioxidants which areof particular utility abilizing oxidizable hydrocarboncompositions against its , the 'objectionable effect of oxidation. v

It is another object'of this invention to provid e "ita proved antioxidants which are normally liquidgandwhich are readily soluble in petroleum "products.

- Another object of the invention is to improve petroleum fuels by incorporating thereina new and highly effective antioxidant capable of reducing gum formation to an unobjectionable level.

' blehydrpcarbon suchras a petroleum derivative or rubber v ;-;These materials thus Other objects will be apparent from the description'and the claims which follow. ;'1\These and other objects are attained by meansof this invention, which comprises stabilizing a normally oxidizaby incorporating therein'a stabilizing amount 01: aN

in which R R and R are the same or different alkyl groups.

- giving particularly advantageous results. The antioxidants of this invention give effective stabilization over a wide range (pf-concentrations; althoughconcentrations. of

"0.001% to 1.0% are preferablyfemployed'for practical purposes."'Largenamounts, suchiasup to 5% or even 10%"by weight based on the weight 'of the materialIbeing stabilized, can be employed with excellent results, fal- N ghl -trialkyl-l,3,5 benzenetriamine in which the: alkyl I The alkyl groups can be either straight or branched chain groups, with the branched alkyl radicals The excess amine was then removed by distilling undei reduced pressure, followed by distillation of the residue to give the antioxidant. This procedure can be used successfully for preparing any of the antioxidants of this invention such as -N ,N ,N -trimethyl-1,3,5-benzenetri amine which has a boiling point of C. at pressures below 0.1 mm., N ,N ,N -tris(n-'butyl) -l,3,5-benzenetriamine,- which is a brown oilv boiling at 190-199" C; at 011 mm. pressure, N ,N ,N -tris(sec butyl) 1,3,5-benzeneti'iamine boiling at C. 'at 0.1 mm. pressure, and N ,N ,N '-;tris(2 ethylhexyl) 1 1,3,5 benzenetriamine boiling "at '193 C. at 0.05 'to 0.10 mm. pressure. The

other antioxidants as defined herein wherein the alkyl groups are the same or difierent groups and contain 1 to 8 carbon atoms are readilyp'repared in'similar fashion.

In the preparation of the various triamines embodying the invention, the amine employed will determine the final product obtained. Thus, for example, methylamine gives the corresponding N ,N ,N -i:'ri(methylamino)' compound, and thef'reaction can be readily carried'o'ut in aqueous solution. In the preparation of the compounds set ,out

above,Qn-butyl amine, 'secrbutyl amine and 2-ethylhexyl aminewere employed to give the corresponding benzene} trianiines. As will appear more fully hereinafter, [any of the benzenetriamines wherein 'theN-alkyl groups con-f tain'from 1 to 8 carbon'atoms can be employed in practicing the invention. The antioxidants in which the alkyl groups contain from 3 to 5 carbon atoms are particularly active, although any of the other compounds can be used with; excellent results. The branched chain alkyl "groups appear to give compounds having a slightly higher degree of antioxidant-activity than the compounds in which the alkyl groups have a straight chain, Not only'do the anti-' oxidants embodying the invention have a high degree of activity, but they possess the further advantages of being oils, and of being readily blended into hydrocarbons such as the petroleum derivatives, :The normally liquidcharacter of the antioxidants of this invention removes the possibility of the antioxidant crystallizing from'the sub strate being stabilized. In this regard, the trialkyl benzene tn'amines oifer advantages over the] 'triaryl" benze'n'etriamines which. are also effective antioxidants. I V

The subject stabiliz'rsfare compatible with and can be employed in conjunction with other types of common additives'suchasidyes, metal deactivators, tetraethyllead .fiu'id, and synergists. .7 l 7 r a The high deg ree of ant oxidant activity of'various iiia-I terialsfembodying this invention ina variety'of hydro; carbon, compositions is illustratedby the following exg amples'of preferred embodiments thereof. similarresults are obtained with any of the other'trialkyl'benzenetri? I aminesiasdefined hereinxwiththese or other normally oxidizable hydrocarbon compositions;

3 EXAMPLE 1 The cracked gasolinesare a typical example ofhydrocarbon materials which are deleteriously afiected by oxidation. In Table 1, typical results are shown for the stabilization of a Pennsylvania blend of catalytic and thermal stocks. The ability of the antioxidants to increase the induction period of this representative cracked gasoline was determined by the oxygen bomb stability test described in Industrial and Engineering Chemistry, 24, 1375 (1932). The concentration of 26 lbs. of antioxidant in 1000 bbl. of" gasoline represents an antioxidant concentration of approximately 0.01%. As can be seen from the table, the induction period: at such concentrations was increased from 350% to morethan 500%. over the induction period for the-same gasoline containing no added antioxidant.

Table 1.--A ntixidant potency in craekedf gasoline Leaded aviation gasoliues. are subjectto oxidatiye dc: terioration which results in the formation of both; soluble and insoluble gums. In such fuels, stabilization of both the tetraethyllead and the hydrocarbonis required, since elements from both have been found in thfiid eterioration products. The improved results obtainedQusingthe antioxidants of this invention in a typicallleaded aviation gasoline are shown in Table 2. The degree of stabilization was determined by the accelerated stability test commonly referred to asthe 16-hour accelerated gum? test. In this procedure, ZOO-ml. samples of gasolinein glass bottles are exposed in stainless, steel bombs to 100 p. s. i. of oxygen for 16 hours at 212 F. After cooling, the content of soluble gum and insoluble gum is determined, and the sum of these two values is designated accelerated gum. The gasolineemployedin the tests shown in Table 2' was acornmercial 115-145 octane fuel containing 4.6 ml. of tetraethyllead per gallon. As can be seen-from thedata set. out in Table 2, the antioxidants of this inven- Jet engine fuels contain no tetraethyllead but suffer from oxidative deterioration which results inthe forma: tion of soluble andinsoluble gums. The jet fuel stability is. commonly. determined by an accelerated gum-test, similar: to the 16-hour-accelerated:gum test described in the preceding example, except that a higher evaporation temperature is used. in determining th'esoluble gum. in jet fuel. 'In Table 3 the dataare set out showingthe utility of the antioxidants of this invention in stabilizing a jet fuel comprising a blend of catalytic, thermal and straight-run gasolines plus naphtha. As can be seen from Table 3, the total quantity of gum formed in an unstabilized jet fuel amounted to 412 mg. per ml. whereas the stabilized compositions containing less than 0.01% of antioxidant had total gum contents in the range of 16-35 mg. per 100 ml.

Table 3.Anzi0xidant potency in jet fuel Concn. in 16-11:. Accelerated Jet Fuel, Gum, nag/100 n11. Antioxidant 1b./l,000

bbl.

S01. Insol.

None 411. 6 0. 4

amino 16 18. 8 2. 6 N N N -tris (sec-butyl) 1, 3, 5-benzenetrlamine 16 16. 2 0. 4 N ,N ,N -tris(2-ethylhexyl)-1,3,5-benzenetriamine 16 33. 4 0. 3

Similar results are obtained with the other trialkyl benzenetriamines as defined herein. The trialkyl benzenetriamines having the same alkyl group in each of the 1, 3 and 5 positions are preferably employed, but mixed trialkyl benzenetriamines can be suitably employed and arereadily prepared by reacting a mixture of amines with phloroglucinol. The, antioxidants of this invention are also suitable for use in other petroleum derivatives such as fuel oils, lubricating oils, and the like, as well as such materials as vegetable oils, rubber, plastics, waxes, and. similarmaterials which are normally subject to oxidation.

The invention thus provides a highly elfective class of stabilizers which impart excellent oxidative stability to hydrocarbon compositions normally subject to objection-v ablefamounts of oxidation. The materials embodying the invention are readily incorporated into the compositions to be stabilized and have no tendency to crystallize out of such compositions.

Although the invention has been described in detail with particular reference to certain preferred embodiments thereof, variations and modifications can be etfected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

We'claim:

' 1. An antioxidant of the formula NH Ra R NH -NHR2 R and R arethe same alkyl groups of 1-8 canbon atoms.-

8. Gasoline stabilized against oxidation with. 0.001- 1.0% weight of-.N ,N ,N. trimethyl 1,3,5 benzenetriamine.

re n R1 References Cited in the file of this patent UNITED STATES PATENTS Dryer June 14, 1938' Gilbert May 9, 1944 Von Bramer et a1 Aug. 7, 1945 Walters Feb. 19, 1946 Prichard Mar. 9, 1954 Krueger' July 20, 1954 

7. GASOLINE STABILIZED AGAINST OXIDATION WITH 0.0011.0% BY WEIGHT OF AN ANTIOXIDANT OF THE FORMULA 